A graphical representation used to analyze the forces exerted on a single system by its environment. Below are the steps to follow for drawing the free-body diagram of a box that you push along a smooth surface.
Step 1. Draw a sketch of the situation described in the problem.
Step 2. Circle the object (objects) of interest in the sketch. This is called the system. (In this example the system contains only one object: the box.)
Step 3. If the object in the system is small or you consider only its center of mass (ignoring any rotation) you can think the object to be a point particle. Draw a dot to represent the object.
Step 4. Identify the objects outside the system (external objects) that interact with the system. Decide what objects exert forces and which are irrelevant because they do not. (In this example the surface, the Earth and You are "pushing").
Step 5. Draw arrows representing the forces originated by the external interactions that affect the behavior of the system. Draw the tails of these arrows beginning on the particle dot. The lengths of the arrows should represent the relative magnitudes of the forces, and the direction should indicate the direction of the forces.
Step 6. Label the forces in the diagram. Identify the external object that causes each force and also the object on which the force is exerted. A good habit is to use clear labels indicating the object outside the system that is exerting the force on the object inside the system. (In this example, FYou on Box, means the force that You exert on the Box).
|
